1. Field of the Invention
The present invention relates to. a liquid crystal display device (LCD), and more particularly to a multi-domain liquid crystal display device capable distorting electric field and shielding light.
2. Description of the Related Art
Recently, a LCD has been proposed where the liquid crystal is not aligned and the liquid crystal is driven by side electrodes insulated from pixel electrodes. FIG. 1 is a sectional view of pixel unit of the conventional LCDs.
Regarding conventional LCDs, a plurality of gate bus lines arranged in a first direction on a first substrate and a plurality of data bus lines arranged in a second direction on the first substrate divide the first substrate into a plurality of pixel regions.
A thin film transistor (TFT) applies image signal delivered from the data bus line to a pixel electrode 13 on a passivation layer 4. The TFT is formed on each pixel region and comprises a gate electrode, a gate insulator, a semiconductor layer, a source electrode, and a drain electrode, etc.
Side electrode 15 is formed surrounding the pixel electrode 13 on the gate insulator, thereon passivation layer 4 is formed over the whole first substrate, and a part of pixel electrode 13 overlaps side electrode 15.
Alternatively, pixel electrode 13 is formed on the gate insulator and passivation layer 4 is formed over the whole first substrate. Afterward, side electrode 15 is formed as overlapping a part of pixel electrode 13. Moreover, it is possible to pattern the pixel electrode 13 by etching and dividing the pixel region.
On a second substrate, a common electrode 17 is formed and together with pixel electrode 13 applies electric field to a liquid crystal layer. Side electrode 15 and open area (slit) 19 distort the electric field applied to the liquid crystal layer. Then, liquid crystal molecules are variously driven in a unit pixel. Thus, when voltage is applied to the LCD, dielectric energy due to the distorted electric field arranges the liquid crystal directors in a needed position.
In the LCDs, however, open area 19 in common electrode 17 or pixel electrode 13 is necessary, and the liquid crystal molecules could be driven stably when the open area is wider. If the electrodes do not have a slit or the width of the slit is narrow, the electric field distortion needed to divide the pixel region becomes weak. Then, when voltage over a threshold voltage, Vth, is applied, the time needed to stabilize the liquid crystal directors increases.
In particular, the response time can be over 100 msec. At this time, disclination occurs from the area where the liquid crystal directors are parallel with a transmittance axis of the polarizer, which results in a decrease in brightness. Further, according to the surface state of LCDs, the liquid crystal texture has an irregular structure.
Accordingly, the present invention is directed to a LCD that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a LCD having a wide viewing angle from a multi-domain effect.
Another object of the present invention is to provide a LCD having high brightness by stable arrangement of liquid crystal molecules.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve the objects and in accordance with the purpose of the invention, as embodied and broadly described herein, a multi-domain liquid crystal display device comprises first and second substrates facing each other; a liquid crystal layer between the first and second substrates; a plurality of gate bus lines arranged in a first direction on the first substrate and a plurality of data bus lines arranged in a second direction on the first substrate to define a pixel region; a thin film transistor positioned at a crossing area of the data bus line and the gate bus line and comprising a gate electrode, a semiconductor layer, and source/drain electrodes; a pixel electrode in the pixel region; a field-affecting electrode on the second substrate; a color filter layer on the field affecting electrode; and a common electrode on the color filter layer.
In another aspect, the multi-domain liquid crystal display of the present invention comprises first and second substrates facing each other; a liquid crystal layer between the first and second substrates; a plurality of gate bus lines arranged in a first direction on the first substrate and a plurality of data bus lines arranged in a second direction on the first substrate to define a pixel region; a thin film transistor positioned at a crossing area of the data bus line and the gate bus line and comprising a gate electrode, a semiconductor layer, and source/drain electrodes; a pixel electrode in the pixel region; a subsidiary electrode on a the second substrate; a color filter layer on the subsidiary electrode; a common electrode on the color filter layer; and an alignment layer on at least one of the first and second substrates.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.